Many thanks to samtregar who replied to my 685965question and put me on the road of discovery of $^S

In first days of my adventure in Perl, I was reading almost montly the tantric page of the special variables thinking: 'mmh if i knew how to use all of them it will be a big advance..'

sam now point me to one of them, $^S ,it seemed to me not so usefull: 'if the state of the Perl interpreter is incorrect my little skills connot do nothing..'

Then I go to the docs and they say:

 
$^S

Current state of the interpreter.

    $^S         State
    ---------   -------------------
    undef       Parsing module/eval
    true (1)    Executing an eval
    false (0)   Otherwise

The first state may happen in $SIG{__DIE__} and $SIG{__WARN__} handler
+s.
[download]

..and SuperSearch is my friend and it comes 607376, 315182 (where I dont well understand the ysth's reply) and 309692 where diotalevi and Aristotle point to another way to catching smarter..

So I wrote a little test script:

#!/usr/bin/perl
use strict;
use warnings;

close STDERR;
$|++;
my $contaerrori= 0;
$SIG{__WARN__} = sub { ++$contaerrori;print STDOUT "[WARN] ",@_ };
$SIG{__DIE__} = sub  {
                        print STDOUT "[CRITICAL ERROR]\t",@_;
                        if  ($^S == 1) { print  "\tPerl interpreter   
+  1 (Executing an eval)\n\tCONTINUE RUNNING\n"}
                        elsif ($^S == 0){ print "\tPerl interpreter   
+  0 (Otherwise)\n\tSTOP\n"}
                        else { print            "\tPerl interpreter un
+def (Parsing module/eval)\n"}
                        print "\n";
                        };
######################################################################
+##########
# HERE THE TESTS
######################################################################
+##########

print "\nNATURAL END OF PROGRAM : ",$contaerrori," WARN",($contaerrori
+ eq 1 ? '' : 'S' )," IN $0\n";
[download]

The snippets to tests are the following:

#A
print $a."\n";
#B
require AAAAAA;
#C
eval { require BBBBB; } or do { warn "  cannot load the mobule BBBBB \
+$^S = $^S\n";
                                print "\ttrying with another module: C
+CCC\n\n";
                                eval { require CCCC; } or do {warn "ca
+nnot load the mobule CCCC \$^S = $^S\n";};
                                if ( $@ ) {warn "no hope with modules 
+today..\n\n";die}
                                else {print "\tsuccesfully loaded CCCC
+\n" ;}

                                };
#D
eval { 0 } or do { warn "zero is not true \$^S = $^S\n"; };
#E
eval { undef } or die "undef is not enough \$^S = $^S\n";
#F
eval {require AAAAAA;};
if ($@) {
        local $SIG{'__DIE__'} = 'DEFAULT';
        die "default die : $@";
}
[download]

These give this results:

#A
[WARN] Use of uninitialized value in concatenation (.) or string at wa
+rn-die.pl line 18.

NATURAL END OF PROGRAM : 1 WARN IN warn-die.pl
#B
[CRITICAL ERROR]    Can't locate AAAAAA.pm in @INC (@INC contains: C:/
+Perl/site/lib C:/Perl/lib .) at warn-die.pl line 20.
    Perl interpreter     0 (Otherwise)
    STOP
#C
[CRITICAL ERROR]    Can't locate BBBBB.pm in @INC (@INC contains: C:/P
+erl/site/lib C:/Perl/lib .) at warn-die.pl line 21.
    Perl interpreter     1 (Executing an eval)
    CONTINUE RUNNING

[WARN]   cannot load the mobule BBBBB $^S = 0
    trying with another module: CCCC

[CRITICAL ERROR]    Can't locate CCCC.pm in @INC (@INC contains: C:/Pe
+rl/site/lib C:/Perl/lib .) at warn-die.pl line 23.
    Perl interpreter     1 (Executing an eval)
    CONTINUE RUNNING

[WARN] cannot load the mobule CCCC $^S = 0
[WARN] no hope with modules today..

[CRITICAL ERROR]    Can't locate CCCC.pm in @INC (@INC contains: C:/Pe
+rl/site/lib C:/Perl/lib .) at warn-die.pl line 23.
    ...propagated at warn-die.pl line 24.
    Perl interpreter     0 (Otherwise)
    STOP
#D
[WARN] zero is not true $^S = 0
NATURAL END OF PROGRAM : 1 WARN IN warn-die.pl
#E
[CRITICAL ERROR] undef is not enough $^S = 0
    Perl interpreter     0 (Otherwise)
    STOP
#F
[CRITICAL ERROR]Can't locate AAAAAA.pm in @INC (@INC contains: C:/Perl
+/site/lib C:/Perl/lib .) at warn-die.pl line 25.
    Perl interpreter     1 (Executing an eval)
    CONTINUE RUNNING
[download]

I think samtregar intended something like test #C when told me about error catching: when it fail to load the second module I choose to die normally and Perl says: ...propagated at warn-die.pl line 24.

In the #F test localize the handler to the DEFAULT seems not working.

is this the correct way to handle warn and die?
I remember somewhere is said that are "pseudo-signal", in which sense?

thank for the attention Lor*